1. Field of the Invention
The present invention relates to a night vision system, and more particularly to a dual mounting assembly for a night vision system usable in either a helmet-mounted or a face mask-mounted configuration.
2. Description of Related Art
Night vision systems are commonly used by military and law enforcement personnel for conducting operations in low light or night conditions. Night vision systems are also used to assist pilots of helicopters or airplanes in flying at night. Such night vision systems either take the form of binoculars, having separate eyepieces for each eye, or monoculars, having only a single eyepiece.
A night vision system intensifies the ambient light to produce an image. These systems require some residual light, such as moonlight or starlight, in which to operate. The ambient light is intensified by the night vision system to produce an output image which is visible to the human eye. The present generation of night vision systems utilize image intensification technologies to intensify the low level of visible light and also make visible the light from the infrared spectrum. The image intensification process involves conversion of the received ambient light into electron patterns and projection of the electron patterns onto a phosphor screen for conversion of the electron patterns into light visible to the observer. This visible light is then viewed by the operator through a lens provided in the eyepiece of the system.
It is common for operators of night vision systems to desire hands-free operation, in which binocular or monocular systems can be mounted to a mask worn on the operator's face. The typical face mask mounting assembly comprises a bar or rod having a plurality of cushion plates attached thereto. The bar would partially encircle the operator's face, and the cushion plates would press against specific points on the face, such as the cheeks and the forehead. The bar is held to the face by use of a strap which wraps around the head and connects to the bar at two places. At the center of the forehead portion of the bar, a mount is provided which would engage the binocular or monocular system.
Face mask mounting is not always desirable, since the mask interferes with the wearing of a helmet. If an operator intends to wear a standard ballistic helmet, the mask must be first adjusted to the operator's face prior to putting the helmet on. The operator first adjusts the mask for alignment of the night vision system with the eyes and then tightens the mask so that it remains in the adjusted position. When the helmet is put on the operator's head, the bulk and weight of the helmet frequently interferes with the upper portion of the face mask. This forces the mask downward relative the operator's face, knocking the night vision system out of alignment with the operator's eyes. The operator must then readjust the mask to accommodate the weight and bulk of the helmet. Alternatively, the operator can readjust the helmet so that it rides higher on the head, and does not interfere with the mask. However, this usage of the helmet is dangerous for the operator, since it removes the temples, forehead and back of the head from protection by the helmet.
If the operator is wearing a monocular system, it is often necessary to switch the monocular from eye to eye. To accommodate this, one type of prior art mounting assembly utilizes a pivoting system in which the monocular is pivoted from the left eye position to the right eye position. A significant problem with this configuration is that it is time-consuming to move the monocular from one eye to the next. The monocular must be readjusted in the new position to accommodate the precise position of the operator's eye. The distance between an operator's eyes, known as the inter-pupillary distance (IPD), varies with each person. In addition, the angle formed between the operator's head and the normal line of sight of the operator's eyes, known as elevation, also tends to vary slightly with each person. Both of these dimensions must be carefully adjusted so that the operator can comfortably use the monocular system. While the time required to make the configuration change and adjustment may be slight, it could mean the difference between life and death of an operator.
Monoculars which attach to center located mounting assemblies have the additional problem of interfering with the operator's use of the unaided eye. For example, it is increasingly common for operators to use externally mounted night vision monoculars, such as provided on a weapon, in addition to the face mask mounted monocular. The operator would typically use the face mask mounted monocular for one eye, and the weapon mounted monocular for the second or unaided eye. In this configuration, a high power, or telescopic lens would typically be used on the weapon, and a unitary power lens used on the face mask mounted system. If the center mounted night vision monocular obstructs too large a portion of the operator's face, or extends too far in the direction of the unaided eye, the operator would be unable to use the weapon mounted monocular.
Another type of prior art mounting assembly avoids using a center mounting assembly by providing a horizontal bar mounted to the front of a face mask above the operator's eyes, to which a night vision monocular is attached. A locking screw holds the monocular in a position on the bar. The operator slides the monocular along the bar to move it from proximity with one eye to the second eye. This presents the same problem to the operator as experienced with the pivoting center mount, since each time the position of the monocular is changed, the operator must recalibrate the new position with his eye's IPD and elevation to effectively use the monocular.
Another problem with each of these mounting assemblies is that they can typically accommodate only the use of an individual type of night vision system. If an operator is utilizing a monocular system with a single eye, and wishes to change to dual eye or binocular usage, the operator must remove the monocular system and replace it with a binocular type system. It would not be possible to use two monocular systems simultaneously since there is only a single mounting assembly. As described above, replacement of a first type with a second type would generally require a readjustment of the mounting assembly for alignment of the replacement night vision system with the operator's eyes. It also requires the operator to have available both a binocular and a monocular night vision system.
An additional problem experienced by operators of night vision systems is the temporary storage of the night vision system when it is not in use. When removed from the mounting assembly, it is common for night vision monoculars or binoculars to be either stowed in a pocket or pouch, or suspended from a lanyard which hangs from the operator's neck. However, certain circumstances render it difficult for an operator to quickly locate the device and install it in its operational position on the mounting assembly. For example, if the operator is in a crouched or reclined position, such as during reconnaissance, the operator may not be able to retrieve the device without altering the position or making unnecessary or extraneous movements. Moreover, since a soldier's available storage space is so limited, it would be advantageous to provide alternative stowing methods for such night vision equipment.
Thus, it would be desirable to provide a night vision system which could be easily and rapidly switched between an operator's eyes. It would be further desirable to provide a mounting assembly for a binocular or monocular to be used in conjunction with either the wearing of a helmet, or in association with a face mask. It would also be desirable to provide a mounting assembly for a night vision monocular which enables rapid and accurate readjustment to accommodate an operator's individual IPD and elevation. It would also be desirable to provide a mounting assembly for a night vision monocular which leaves sufficient clearance for the simultaneous use of an externally provided night vision monocular with the unaided eye. It would also be desirable to provide a mounting assembly for a night vision system enabling the simultaneous usage of two monocular systems to simulate a binocular effect. It would also be desirable to provide a mounting assembly for a night vision system which enables the monocular to be temporarily stored when not in use.